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Fix some edge cases in fmpz_set_str #2366

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Merged
merged 1 commit into from
Oct 28, 2025
Merged

Fix some edge cases in fmpz_set_str #2366

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14 changes: 10 additions & 4 deletions src/fmpz/set_str.c
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Original file line number Diff line number Diff line change
Expand Up @@ -202,10 +202,6 @@ fmpz_set_str(fmpz_t res, const char * str, int base)
slong slen, i;
int neg = 0;

/* Let GMP handle unusual bases. */
if (base != 10)
return fmpz_set_str_fallback(res, str, base, 0);

/* Allow leading whitespace. */
while (isspace(str[0]))
str++;
Expand All @@ -214,8 +210,18 @@ fmpz_set_str(fmpz_t res, const char * str, int base)
{
str++;
neg = 1;

while (isspace(str[0]))
str++;
/* Checked specially, otherwise GMP might handle the second minus */
if (str[0] == '-')
return -1;
}

/* Let GMP handle unusual bases. */
if (base != 10)
return fmpz_set_str_fallback(res, str, base, neg);

slen = strlen(str);

/* Allow trailing whitespace. */
Expand Down
78 changes: 78 additions & 0 deletions src/fmpz/test/t-set_str.c
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Expand Up @@ -14,6 +14,15 @@
#include "ulong_extras.h"
#include "fmpz.h"

typedef struct
{
int base;
const char* input;
int rv;
slong result;
}
testcases_t;

TEST_FUNCTION_START(fmpz_set_str, state)
{
int i;
Expand Down Expand Up @@ -119,5 +128,74 @@ TEST_FUNCTION_START(fmpz_set_str, state)
mpz_clear(b);
}

/* Test specific cases to ensure proper edge-case handling */
testcases_t cases[] =
{
{10, "", -1, 0},
{ 0, "", -1, 0},
{10, "0", 0, 0},
{ 0, "0", 0, 0},
{10, "-", -1, 0},
{ 0, "-", -1, 0},
{10, "-0", 0, 0},
{ 0, "-0", 0, 0},
{10, "- 2", 0, -2},
{ 0, "- 2", 0, -2},
{10, " -2", 0, -2},
{ 0, " -2", 0, -2},
{10, " - 2", 0, -2},
{ 0, " - 2", 0, -2},
{10, "- 2", 0, -2},
{ 0, "- 2", 0, -2},
{10, "- 2 ", 0, -2},
{ 0, "- 2 ", 0, -2},
{10, "--2", -1, 0},
{ 0, "--2", -1, 0},
{10, "1 2 3", 0, 123},
{ 0, "1 2 3", 0, 123},
{10, "1-2", -1, 0},
{ 0, "1-2", -1, 0},
{10, "f", -1, 0},
{ 0, "f", -1, 0},
{ 0, "0x0", 0, 0},
{ 0, "-0x0", 0, 0},
{ 0, "0xf", 0, 15},
{ 0, "-0xf", 0, -15},
{ 0, "--0xf", -1, 0},
{ 0, "0x f", 0, 15},
{ 0, "-0x f", 0, -15},
{ 0, "- 0x f", 0, -15},
{ 0, "0 xf", -1, 0},
{16, "0x10", -1, 0},
{ 0, "0x10", 0, 16},
{ 2, "0b10", -1, 0},
{ 0, "0b10", 0, 2},
{ 8, "010", 0, 8},
{ 0, "010", 0, 8},
{10, "010", 0, 10},
};
for (i = 0; i < sizeof(cases) / sizeof(cases[0]); i++)
{
fmpz_t a;
int ret;

fmpz_init(a);
ret = fmpz_set_str(a, cases[i].input, cases[i].base);

if (ret != cases[i].rv || ret == 0 && fmpz_get_si(a) != cases[i].result)
{
flint_printf("FAIL:\n");
flint_printf("case = %d\n", i);
flint_printf("base = %d, str = %s\n", cases[i].base, cases[i].input);
flint_printf("rv = %d, expected = %d\n", ret, cases[i].rv);
flint_printf("result = "); fmpz_print(a);
flint_printf(", expected = %ld\n", cases[i].result);
fflush(stdout);
flint_abort();
}

fmpz_clear(a);
}

TEST_FUNCTION_END(state);
}